JP4736532B2 - Hydraulic control device - Google Patents

Description

  The present invention relates to a hydraulic pressure control device, and more particularly, to a hydraulic pressure control device that generates a hydraulic pressure by driving a hydraulic pressure generating mechanism disposed in a medium liquid.

  For example, in a hydraulic control device in a brake device of a vehicle, a hydraulic pressure is generally applied to a wheel cylinder by driving a hydraulic pressure generating mechanism including an eccentric cam and a piston that are generally arranged in a medium liquid by a motor. In such a hydraulic pressure generating mechanism, a negative pressure is generated by a centrifugal force generated in the flow of the medium liquid or in the medium liquid around the components of the driven hydraulic pressure generating mechanism. The negative pressure may cause air dissolved in the medium liquid to form bubbles. If these bubbles are left unattended, the responsiveness of the pump may be deteriorated due to contraction of the bubbles.

For this reason, for example, in Patent Document 1, when it is detected that the pump has shifted from the operating state to the stopped state while the switching valve is closed, the liquid passage that connects the suction side of the pump and the master cylinder side is provided. A technique for opening a solenoid valve provided in the middle for a predetermined time has been proposed. Further, for example, Patent Document 2 proposes a technique in which a pump is operated at least once for a predetermined time at the start of operation of an automobile, and a suction valve that is incorporated in a suction pipe and shut off is opened for a certain time during the operation of the pump. Has been. Further, for example, Patent Document 3 proposes a technique for venting the medium liquid by returning the medium liquid directly from the wheel cylinder to the tank when the pedal is released. For example, in Patent Document 4, a technique for reducing the reaction shock felt by the brake pedal at the start of the lock prevention adjustment by continuously or intermittently decreasing the supply voltage of the motor from the decrease in the pressure drop signal to the stop of the motor. Has been proposed. For example, Patent Document 5 proposes a technique of masking pump noise of a trochoid gear type fuel pump with engine sound.
Japanese Patent Laid-Open No. 9-240457 JP-A-5-213177 Japanese Patent Laid-Open No. 9-20232 JP-A-4-232164 JP 2002-48023 A

  Even in the above-described pump, for example, when the motor that drives the hydraulic pressure generating mechanism is stopped, the motor is suddenly stopped so that minute bubbles generated in the hydraulic pressure generating mechanism are combined with each other and become large. It may grow into bubbles. It is difficult for the bubbles that have grown in this way to be dissolved again in the medium liquid. Further, in the pump as described above, if the bubbles generated in the hydraulic pressure generating mechanism can be removed from the hydraulic pressure generating mechanism and washed away to the reservoir, it is possible to suppress the deterioration of the pump response due to the bubbles. It is.

  This invention is made | formed in view of such a subject, The objective is to reduce the bubble which generate | occur | produces in the hydraulic pressure generation mechanism arrange | positioned in a medium liquid, or to suppress the growth of a bubble.

In order to solve the above-described problem, a hydraulic pressure control device according to an aspect of the present invention is a hydraulic pressure control device applied to a brake device of a vehicle, and includes a hydraulic pressure generation mechanism disposed in a medium liquid. When a motor for generating a hydraulic pressure by driving the hydraulic pressure generating mechanism, and a motor control means for controlling the rotation of the motor, Ru comprising a. The hydraulic pressure generating mechanism has an eccentric cam, a piston that contacts the eccentric cam, a rotating shaft that transmits the drive of the motor to the eccentric cam, and a bearing that slides on the rotating shaft, and the eccentric cam is driven by the motor. Thus, the piston reciprocates to generate hydraulic pressure, and the motor control means gradually decreases the motor rotation speed by gradually decreasing the duty for supplying current to the motor when the pump is stopped. Reduce the motor speed to stop.

According to this aspect, it is possible to suppress the generation and growth of minute bubbles generated in the hydraulic pressure generation mechanism by suddenly stopping the motor, and to promote the bubbles to be dissolved in the medium liquid again. it can.

Further, according to this aspect, the rotational speed of the motor can be gradually reduced by simple control, and the generation of bubbles in the medium liquid around the eccentric cam, the rotating shaft, or the bearing can be suppressed.

There may be further provided a switching valve that is disposed in a liquid path different from the liquid path in which the hydraulic pressure generating mechanism is disposed, and that communicates or blocks between the accumulator and the reservoir. The pump communicates with the reservoir, and is provided to apply hydraulic pressure to the accumulator by driving the hydraulic pressure generation mechanism. The switching valve communicates between the accumulator and the reservoir when the pump is stopped. You may let them. According to this aspect, bubbles generated in the hydraulic pressure generating mechanism can be pushed away to the reservoir when the pump is stopped, and deterioration of pump response due to the bubbles can be suppressed.

  The switching valve has a pressure increasing valve for communicating or blocking between the accumulator and the wheel cylinder, and a pressure reducing valve for communicating or blocking between the wheel cylinder and the reservoir, and opens the pressure increasing valve and the pressure reducing valve. Thus, the accumulator and the reservoir may be communicated with each other. According to this aspect, the accumulator and the reservoir can be communicated with each other by opening the pressure increasing valve for increasing the wheel cylinder pressure and the pressure reducing valve for reducing the pressure.

  The hydraulic pressure generating mechanism has an eccentric cam, a piston that contacts the eccentric cam, a rotating shaft that transmits driving to the eccentric cam, and a bearing that slides on the rotating shaft, and the eccentric cam is driven, The piston may reciprocate to generate hydraulic pressure. According to this aspect, generation | occurrence | production of the bubble in the medium liquid around an eccentric cam, a rotating shaft, or a bearing can be suppressed.

There may be further provided a switching valve that is disposed in a liquid path different from the liquid path in which the hydraulic pressure generating mechanism is disposed, and that communicates or blocks between the accumulator and the reservoir. The pump is in communication with the reservoir, and is provided to apply hydraulic pressure to the accumulator by driving the hydraulic pressure generation mechanism. The switching valve is in a predetermined state in which the pump is stopped and the background noise of the vehicle is high. The accumulator and the reservoir may be communicated with each other . According to this aspect, the bubbles generated in the hydraulic pressure generating mechanism can be pushed away to the reservoir, the deterioration of the pump response due to the bubbles can be suppressed, and the operation sound of the switching valve can be reduced by the background noise of the vehicle. It can be inconspicuous.

  The predetermined state may be when the speed of the vehicle becomes greater than a predetermined value. According to this aspect, since the switching valve is operated when the vehicle speed is high, the operation sound of the switching valve can be made inconspicuous.

  The predetermined state may be when the engine speed of the vehicle becomes greater than a predetermined value. According to this aspect, since the switching valve is operated when the engine speed is high, the operating sound of the switching valve can be made inconspicuous by the engine sound.

  Also in this aspect, the switching valve includes a pressure increasing valve that allows communication between the accumulator and the wheel cylinder, and a pressure reducing valve that enables communication between the wheel cylinder and the reservoir. The accumulator and the reservoir may be communicated with each other by opening the pressure reducing valve. The hydraulic pressure generating mechanism has an eccentric cam, a piston that contacts the eccentric cam, a rotating shaft that transmits driving to the eccentric cam, and a bearing that slides on the rotating shaft, and the eccentric cam is driven. Thus, the piston may reciprocate to generate a hydraulic pressure.

  According to the fluid pressure control device of the present invention, bubbles generated in a fluid pressure generating mechanism arranged in the medium liquid can be reduced or bubble growth can be suppressed.

  Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is an overall configuration diagram of a hydraulic system 150 according to the first embodiment. The hydraulic system 150 mainly includes an actuator 80 and a master cylinder 14 other than the actuator 80.

  The brake pedal 12 is provided with a stroke sensor 46 that detects the depression stroke. The master cylinder 14 pumps the brake fluid, which is a medium fluid, in response to the depression operation of the brake pedal 12 by the driver. A dry stroke simulator 13 is provided between the brake pedal 12 and the master cylinder 14.

  One end of a brake fluid pressure control conduit 16 for the right front wheel and a brake fluid pressure control conduit 18 for the left front wheel are connected to the master cylinder 14, and these brake fluid pressure control conduits exhibit the braking force of the right front wheel and the left front wheel, respectively. Are connected to the right front wheel wheel cylinder 20FR and the left front wheel wheel cylinder 20FL. A right master shut-off valve 22FR and a left master shut-off valve 22FL (hereinafter collectively referred to as “master shut-off” as needed) are respectively provided in the middle of the right front wheel brake fluid pressure control conduit 16 and the left front wheel brake fluid pressure control conduit 18. Valve 22 ”), and a right master pressure sensor 48FR and a left master pressure sensor 48FL (hereinafter collectively referred to as necessary) for measuring the master cylinder fluid pressure on the right front wheel side and the left front wheel side, respectively. (Referred to as “master pressure sensor 48”). When the brake pedal 12 is depressed by the driver, the depression is detected by the stroke sensor 46, but the failure of the stroke sensor 46 is assumed and the measurement of the master cylinder hydraulic pressure by the master pressure sensor 48 is also used. Depression is detected. The master cylinder hydraulic pressure is monitored by two pressure sensors from the viewpoint of fail-safe.

  The master shut-off valve 22 is an electromagnetic valve that is normally open (hereinafter referred to as “normally open type”). When the W / C (wheel cylinder) pressure is controlled by the control of the pressure-increasing linear valve 40 and the pressure-decreasing linear valve 42 which will be described later, the W / C (wheel cylinder) pressure is closed, and the wheel cylinder 20 which will be described later is cut off from the master cylinder 14. When these master shut-off valves 22 are opened, the master cylinder 14 and a wheel cylinder 20 described later are brought into communication, and a brake 70 described later is operated by the hydraulic pressure of the master cylinder 14.

  A reservoir tank 26 is connected to the master cylinder 14, a wet stroke simulator 24 is connected via an on-off valve 23, and one end of a hydraulic pressure supply / discharge conduit 28 is connected to the reservoir tank 26. The hydraulic pressure supply / discharge conduit 28 is provided with a plunger pump 400 driven by a motor 32. The discharge side of the plunger pump 400 is a high-pressure conduit 30, and an accumulator 49 and a relief valve 53 are provided. The accumulator 49 accumulates the medium liquid that has been brought to a high pressure within the control range by the plunger pump 400. The relief valve 53 opens when the accumulator pressure becomes abnormally high, and allows the high-pressure medium liquid to escape to the hydraulic pressure supply / discharge conduit 28.

  The high pressure conduit 30 is provided with an accumulator pressure sensor 51 that measures the accumulator pressure. An electronic control unit 200 (hereinafter referred to as “ECU 200”), which will be described later, inputs the accumulator pressure that is the output of the accumulator pressure sensor 51, and controls the motor 32 so that the accumulator pressure falls within the control range to control the driving of the plunger pump 400. To do. Thus, ECU 200, plunger pump 400, and motor 32 constitute a hydraulic pressure control device that controls the accumulator pressure.

  Each of the high-pressure conduits 30 is normally in a closed state (referred to as a “normally closed type”). When necessary, the front right wheel pressure-increasing linear valve 40FR and the left front wheel pressure-increasing linear are used for pressure increase of the wheel cylinder. A right front wheel wheel cylinder 20FR is connected via a valve 40FL, a right rear wheel pressure-increasing linear valve 40RR, and a left rear wheel pressure-increasing linear valve 40RL (hereinafter collectively referred to as “pressure-increasing linear valve 40” as necessary). The left front wheel wheel cylinder 20FL, the right rear wheel wheel cylinder 20RR, and the left rear wheel wheel cylinder 20RL (hereinafter collectively referred to as “wheel cylinder 20” as necessary).

  Each of the wheels of the vehicle (not shown) includes a right front wheel brake 70FR, a left front wheel brake 70FL, a right rear wheel brake 70RR, and a left rear wheel brake 70RL (hereinafter collectively referred to as necessary). (Referred to as “brake 70”), and the brake force is exerted by pressing the brake shoe against the drum by driving the wheel cylinder 20, respectively.

  The right front wheel wheel cylinder 20FR and the left front wheel wheel cylinder 20FL are an electromagnetic flow control valve used for pressure reduction when necessary, that is, a normally closed right front wheel pressure reducing linear valve 42FR that is a linear valve, and a left front wheel pressure reducing pressure. It is connected to the hydraulic pressure supply / discharge conduit 28 via the linear valve 42FL. Further, the right rear wheel wheel cylinder 20RR and the left rear wheel wheel cylinder 20RL are connected to the hydraulic pressure supply / discharge conduit 28 via a normally open right rear wheel pressure reducing linear valve 42RR and a left rear wheel pressure reducing linear valve 42RL, respectively. Connected to. Hereinafter, the pressure reducing linear valves 42FL, 42FR, 42RL, and 42RR are collectively referred to as “the pressure reducing linear valve 42” as necessary.

  In the vicinity of each wheel cylinder 20, a right front wheel W / C pressure sensor 44FR, a left front wheel W / C pressure sensor 44FL, and a right rear wheel W / C pressure sensor 44RR that measure the hydraulic pressure in the wheel cylinder, respectively. A left rear wheel W / C pressure sensor 44RL (hereinafter collectively referred to as "W / C pressure sensor 44" as necessary) is provided.

  FIG. 2 is a functional block diagram of the ECU 200 according to the first embodiment. The ECU 200 has a main control unit 210 including a calculation unit 202, a ROM 204, a RAM 206, an I / O port, and the like by a microcomputer. The I / O port of the main control unit 210 includes the above-described stroke sensor 46, accumulator. A pressure sensor 51, a master pressure sensor 48, and a W / C pressure sensor 44 are connected. The ECU 200 also includes a linear valve control unit 100 that controls the pressure-increasing linear valve 40, a pressure-decreasing linear valve 42, a motor control unit 130 that controls the motor 32, a master cutoff valve control unit 140 that controls the master cutoff valve 22, and the like. The linear valve control unit 100 is connected to the pressure-increasing linear valve 40 and the pressure-reducing linear valve 42, the motor control unit 130 is connected to the motor 32, and the master shut-off valve control unit 140 is connected to the master shut-off valve 22, respectively. Has been.

  The arithmetic unit 202 includes a stroke signal indicating the depression stroke of the brake pedal 12 from the stroke sensor 46, an accumulator pressure signal indicating the accumulator pressure from the accumulator pressure sensor 51, a master pressure signal indicating the master pressure from the master pressure sensor 48, and W / C. A W / C pressure signal indicating the W / C pressure is input from the pressure sensor 44.

  The ROM 204 stores a plurality of programs such as a pressure-increasing linear valve control program and a plurality of tables such as an accumulator pressure setting range determination table. The RAM 206 is used as a work area for data storage and program execution. For example, the calculation unit 202 calculates a target W / C pressure for each wheel based on a stroke signal, a master pressure signal, a W / C pressure signal, and the like using a program stored in the ROM 204.

  The arithmetic unit 202 calculates a PSB (Pressure Servo Brake) command current, which is a control current supplied to the pressure increasing linear valve 40 and the pressure reducing linear valve 42, from the calculated target W / C pressure. The calculated PSB command current is output to the linear valve control unit 100. Upon receiving the PSB command current, the linear valve control unit 100 converts the input PSB command current into a drive signal for driving the linear solenoids of the pressure-increasing linear valve 40 and the pressure-decreasing linear valve 42, and the pressure-increasing linear valve 40. And output to the pressure-reducing linear valve 42. The medium hydraulic pressure obtained by the operation of the driven pressure-increasing linear valve 40 and pressure-decreasing linear valve 42 is fed back to the arithmetic unit 202. As described above, the arithmetic unit 202 performs control so that the W / C pressure of each wheel becomes the target W / C pressure.

  The ECU 200 determines whether or not the accumulator pressure is greater than a predetermined pressure from the accumulator pressure signal input from the accumulator pressure sensor 51. If the accumulator pressure is smaller than the predetermined pressure, the motor control unit 130 of the ECU 200 A drive signal is output to 32. The motor 32 operates in response to the input of a drive signal, and applies hydraulic pressure to the accumulator 49 by driving the plunger pump 400.

  FIG. 3 is an overall configuration diagram of the plunger pump 400 according to the first embodiment. The plunger pump 400 includes a pump housing 310, a first pump 320 and a second pump 360 disposed in the pump housing 310, an eccentric cam unit 420, a drive shaft unit 440, and the like. Among these, the first pump 320, the second pump 360, the eccentric cam unit 420, and the like constitute a hydraulic pressure generating mechanism.

  The drive shaft unit 440 includes a motor drive shaft 442, an engaging portion 444, and the like. The drive shaft 442 is rotatably supported by a first bearing 446. The engaging portion 444 is fixed to the drive shaft 442 and has a positioning hole on the left surface in the drawing.

  The eccentric cam unit 420 includes a rotating shaft 422, an eccentric cam 426, a second bearing 424, a third bearing 428, and the like. An eccentric cam 426 is formed in the vicinity of the center in the axial direction of the rotation shaft 422 so that the center of the outer periphery is eccentric with respect to the rotation center. The inner rings of the second bearing 424 and the third bearing 428 are press-fitted into the rotating shaft 422 on both sides of the eccentric cam 426. A claw portion 430 extending in the radial direction of the rotation shaft 422 is formed on the drive shaft unit 440 side of the rotation shaft 422. By inserting the claw portion 430 into the positioning hole of the engaging portion 444, the rotation of the drive shaft 442 and the rotation of the eccentric cam 426 are coupled.

  The eccentric cam 426 includes a ring 353, a needle bearing 350, and an inner race portion 422a of the rotating shaft 422. The needle bearing 350 is a kind of roller bearing and includes a cage 351 and a plurality of needles 352 held by the cage 351. The ring 353 is attached to the inner race portion 422a of the rotating shaft 422 via a needle bearing 350.

  The two balancers 438 are disposed on both sides of the eccentric cam 426, and are sandwiched between the eccentric cam 426 and the second bearing 424, and the eccentric cam 426 and the third bearing 428, respectively. The balancer 438 is fixed to the rotary shaft 422 so as to be able to rotate together with the eccentric cam 426, and is sandwiched between the inner rings of the second bearing 424 and the third bearing 428 so as not to contact each outer ring. The balancer 438 is attached so as to cancel out the deviation of the center of gravity of the eccentric cam 426, thereby realizing a smooth rotation of the eccentric cam 426.

  The pump housing 310 is provided with a substantially cylindrical bottomed hole having an opening in the right direction in the figure, and the eccentric cam unit 420 is inserted into the bottomed hole. In the eccentric cam unit 420, the second bearing 424 and the third bearing 428 are press-fitted into the bottomed hole, so that the eccentric cam 426 is rotatably fixed to the pump housing 310 together with the rotation shaft 422. After inserting the eccentric cam unit 420 into the bottomed hole, the spacer 434 and the oil seal 436 are attached to the opening of the bottomed hole.

  The pump housing 310 has an opening in the above-mentioned bottomed hole, and is provided with two cylindrical pump holes 322 formed to extend in the vertical direction in the figure so as to face the bottomed hole. ing. By inserting the first pump 320 and the second pump 360 into the two pump holes 322, respectively, the first pump 320 and the second pump 360 are disposed to face the eccentric cam 426.

  The first pump 320 includes a first plunger 326, a cylinder 324, a first suction check valve 335, a first discharge check valve 345, and the like. The first plunger 326 is formed in a cylindrical shape, and slidably contacts the outer periphery of the eccentric cam 426. The first plunger 326 is inserted into a cylindrical cylinder side portion 324 a provided in the cylinder 324. The cylinder 324 is inserted into the pump hole 322, and is fixed by a plug 341 supporting a rear end opposite to the opening side of the cylinder side portion 324a. Thereby, the 1st plunger 326 can be slid to the up-down direction inside the cylinder side part 324a.

  The first plunger 326 is biased in the direction of the eccentric cam 426 by a plunger spring 334 whose end is locked to the cylinder bottom 324 b of the cylinder 324. As a result, the first plunger 326 can reciprocate while the tip portion is in contact with the outer periphery of the eccentric cam 426.

  A suction port 328 is provided in the vicinity of the eccentric cam 426 of the first plunger 326. The suction port 328 is arranged at a position where the suction port 328 is not blocked by the cylinder 324 even when the eccentric cam 426 rotates and the first plunger 326 reciprocates in the vertical direction. Inside the first plunger 326, a suction path 329 that leads from the suction port 328 to the first suction check valve 335 is formed. The suction path 329 is a radial suction path 329a that penetrates in the radial direction of the first plunger 326 including the suction port 328, and a suction path that communicates with the radial suction path 329a, and includes the central axis of the first plunger 326. The axial suction path 329b has an opening at the rear end that extends in the axial direction and is opposite to the side in contact with the eccentric cam 426.

  The first pump 320 has a first suction check valve 335 and a first discharge check valve 345. The first suction check valve 335 is provided above the first plunger 326. The first suction check valve 335 includes a first suction valve ball 330, a suction valve bracket 332, and a suction path 329.

  The intake valve bracket 332 has a substantially U-shaped cross section, and is fixed to the upper surface of the first plunger 326 with the substantially U-shaped opening facing downward. The suction valve bracket 332 is disposed so that the axial suction passage 329b is positioned in the substantially U-shaped opening. A first suction valve ball 330 as a valve element is disposed in a portion surrounded by the suction valve bracket 332 and the first plunger 326. The suction valve bracket 332 is provided with a medium liquid passage port. The first suction valve ball 330 is movable in the suction valve bracket 332 so that the first suction valve ball 330 can be seated in a suction passage 329 serving as a valve seat.

  The cylinder side portion 324a, the cylinder bottom portion 324b, and the first plunger 326 form a first suction chamber 336 that is a low-pressure liquid chamber. The medium liquid sucked through the suction port 328, the radial suction path 329a, and the axial suction path 329b is temporarily stored in the first suction chamber 336.

  A first discharge chamber 346 that is a high-pressure liquid chamber is formed in the upper portion of the cylinder 324 by the upper surface of the cylinder 324 and the plug 341. The first discharge chamber 346 and the first suction chamber 336 communicate with each other through a discharge path 325. The discharge path 325 is formed in the axial direction of the first plunger 326 in the upper part of the first suction chamber 336 of the cylinder 324.

  The first discharge check valve 345 is provided at the rear end of the cylinder 324. The first discharge check valve 345 includes a discharge valve bracket 344, a first discharge valve ball 340, a discharge valve spring 342, and a discharge path 325. The discharge valve bracket 344 also has a substantially U-shaped cross section, and is fixed to the upper surface of the cylinder 324 with the substantially U-shaped opening facing downward. The discharge valve bracket 344 is disposed such that the discharge path 325 is positioned in an approximately U-shaped opening.

  A first discharge valve ball 340 that is a valve element is disposed in a portion surrounded by the discharge valve bracket 344 and the cylinder 324. One end of the discharge valve spring 342 is fixed to the first discharge valve ball 340 and the other end is fixed to a surface of the discharge valve bracket 344 facing the cylinder 324, and the first discharge valve ball 340 is directed to the discharge path 325. Is energized. For this reason, the first discharge valve ball 340 is in a state of being seated on the discharge path 325 as a valve seat when there is no medium liquid flow. On the other hand, the discharge valve spring 342 is separated from the discharge path 325 by the flow of the medium liquid from the discharge path 325 when the first pump 320 discharges the medium liquid, so that the first discharge chamber 346 and the discharge path 325 communicate with each other. The first discharge valve ball 340 is urged by the force.

  The first discharge chamber 346 communicates with an electromagnetic hydraulic valve such as a pressure-increasing linear valve 40 or a pressure-decreasing linear valve 42 via an accumulator 49 that suppresses pulsation of the discharged medium liquid. Further, the electromagnetic hydraulic valve communicates with a wheel cylinder 20 provided on each wheel.

  As described above, when the motor is operated and the drive shaft 442 rotates, the rotating shaft 422 and the rotating shaft 422 are fixed to each other via the engaging portion 444 and the claw portion 430 engaged with the positioning hole of the engaging portion 444. The eccentric cam 426 rotates. Thereby, the drive shaft 442 of the motor, the claw portion 430, and the eccentric cam 426 rotate together.

  As the eccentric cam 426 rotates, the first plunger 326 whose tip is pressed against the eccentric cam 426 reciprocates in the vertical direction. First, when the first plunger 326 starts to move downward, the pressure in the first suction chamber 336 decreases, so the pressure in the discharge path 325 also decreases, and the first discharge valve ball 340 moves to the discharge path 325. It will be in the state still sitting in the opening part. As a result, while the first plunger 326 is moving downward, the first discharge check valve 345 is closed, and the flow of the medium liquid from the first discharge chamber 346 to the first suction chamber 336 is blocked.

  Similarly, when the first plunger 326 starts to move downward, the pressure in the first suction chamber 336 decreases, so that the medium passes from the liquid chamber 312 to the first suction chamber 336 through the suction port 328 and the suction path 329. Liquid flows. The first suction valve ball 330 is separated from the opening of the suction path 329 by the flow of the medium liquid. Thus, while the first plunger 326 is moving downward, the first suction check valve 335 is opened, and the liquid chamber 312 and the first suction chamber 336 communicate with each other.

  When the eccentric cam 426 further rotates and the first plunger 326 starts to move upward, the pressure in the first suction chamber 336 increases, so that the medium liquid starts to flow from the first suction chamber 336 to the suction path 329. . Due to the flow of the medium liquid, the first suction valve ball 330 is seated on the opening of the suction path 329. Thus, while the first plunger 326 is moving upward, the first suction check valve 335 is closed, and the flow of the medium liquid from the first suction chamber 336 to the liquid chamber 312 is blocked.

  Similarly, when the first plunger 326 starts to move upward, the pressure in the first suction chamber 336 increases, so that the medium liquid passes from the first suction chamber 336 to the first discharge chamber 346 through the discharge path 325. Flowing. With the flow of the medium liquid, the first discharge valve ball 340 moves upward and is separated from the opening of the discharge path 325. Thus, while the first plunger 326 is moving upward, the first discharge check valve 345 is opened, and the first suction chamber 336 and the first discharge chamber 346 communicate with each other.

  The eccentric cam 426 rotates and the first plunger 326 reciprocates in the vertical direction, so that the above operation is repeated, and the medium liquid in the liquid chamber 312 flows into the first discharge chamber 346. As a result, the medium liquid is supplied to the wheel cylinder 20 by the first pump 320 via the accumulator 49 and the pressure-increasing linear valve 40.

  The second pump 360 also has the same configuration as the first pump 320, and the medium liquid discharged by the second pump 360 is supplied to the wheel cylinder. The second plunger 362 of the second pump is disposed to face the first plunger 326 with the eccentric cam 426 interposed therebetween. Accordingly, when the first pump 320 is performing the medium liquid suction operation, the second pump 360 can perform the medium liquid discharge operation, and can continuously supply the medium liquid to the wheel cylinder. .

  The second pump has a second suction check valve 365 and a second suction chamber 366. The second suction check valve 365 has a second suction valve ball 364. In addition, the second pump has a second discharge check valve 375 and a second discharge chamber 370. The second discharge check valve 375 has a second discharge valve ball 368.

  The second pump 360 is configured by a structural member having the same shape as the structural member of the first pump 320. As a result, approximately the same amount of medium liquid can be alternately discharged from the first discharge chamber 346 and the second discharge chamber 370 by the first pump 320 and the second pump 360, so that a constant medium liquid is discharged continuously. can do.

  In the plunger pump 400 as described above, the hydraulic pressure generating mechanism such as the first pump 320, the second pump 360, and the eccentric cam unit 420 disposed in the medium liquid in the liquid chamber 312 is a motor as a driving unit. By being driven by 32, a negative pressure is generated around the rotating shaft 422 due to the flow of the medium liquid and the centrifugal force accompanying the rotation of each component constituting the fluid pressure generating mechanism. When this negative pressure reaches a certain level, the air dissolved in the medium liquid becomes minute bubbles. Further, when the hydraulic pressure generating mechanism is driven by the motor 32, the minute bubbles are coupled to each other and grow into larger bubbles. If the bubbles are left unattended, the responsiveness of the plunger pump 400 may be deteriorated due to the contraction of the bubbles.

  In particular, the second bearing 424 and the third bearing 428 arranged in the liquid chamber 312 have fine components constituting them inside. For this reason, when the rotating shaft 422 is driven and the inner ring is rotated with respect to the outer ring, bubbles may be generated around these internal components arranged between the inner ring and the outer ring. In addition, since the eccentric cam 426 and the balancer 438 are both eccentric with respect to the rotating shaft 422, the medium liquid is stirred in the liquid chamber 312 to give a centrifugal force and generate negative pressure. Even bubbles can be generated. In addition, since the needle bearing 350 also includes fine parts such as the cage 351 and the needle 352, air bubbles may be generated in or around the needle bearing 350, like the second bearing 424 and the third bearing 428. is there. In addition, since the rotating shaft 422 also applies a centrifugal force to the medium liquid in the liquid chamber 312 and generates a negative pressure, air bubbles may be generated around the rotating shaft 422.

  When the motor control unit 130 of the ECU 200 receives the detection result of the accumulator pressure sensor 51 and determines that the accumulator pressure has exceeded a predetermined value, the motor control unit 130 stops the generation of the hydraulic pressure by the plunger pump 400. Stop. At this time, in the present embodiment, the motor control unit 130 of the ECU 200 gradually decreases the rotation speed of the motor 32 by PWM control that gradually decreases the duty for supplying current to the motor 32 to rotate the motor 32. Stop. As a result, it is possible to suppress the generation and growth of minute bubbles generated in the hydraulic pressure generating mechanism due to abruptly stopping the motor, and it is possible to promote the bubbles to dissolve again in the medium liquid.

  FIG. 4 is a flowchart showing a stop control process of the hydraulic control apparatus according to the first embodiment. The processing in this flowchart starts when the motor 32 starts operation.

The ECU 200 receives the detection result of the accumulator pressure sensor 51 when the motor 32 is operating, and determines whether or not the accumulator pressure P _acc is equal to or higher than a predetermined pressure P ₀ (S11). When it is determined that the accumulator pressure P _acc is less than the predetermined pressure P ₀ (N in S11), the ECU 200 determines whether or not the accumulator pressure P _acc is equal to or higher than the predetermined pressure P ₀ every predetermined time. repeat.

When it is determined that the accumulator pressure P _acc is equal to or higher than the predetermined pressure P ₀ (Y in S11), the ECU 200 first sets n to 1 (S12) to stop the motor 32 and applies it to the motor 32. the motor voltage _{V p} which, as an initial voltage _{V 0 -a * n (S13)} . Here, a is the slope for reducing gradually the motor voltage V _p. Motor voltage V _p becomes the initial voltage V ₀ and minus the a * n, the rotational speed of the motor 32 is also reduced.

Next, ECU 200 sets n to n + 1 (S14), the accumulator pressure _{P acc} is determined whether or not a predetermined pressure _{P 1} or less (S15). When it is determined that the accumulator pressure P _acc is equal to or lower than the predetermined pressure P ₁ (Y in S15), the accumulator pressure P _acc has to be increased again. Therefore, the ECU 200 is the stop control of the plunger pump 400 in this flowchart. The process ends.

When it is determined that the accumulator pressure P _acc is greater than the predetermined pressure P ₁ (N in S15), the ECU 200 determines whether n is a predetermined number b or more (S16). Here, b, by subtracting the a * b from an initial voltage V _0, the value such that the motor voltage V _p is approximately zero is set. if n is determined to be equal to or greater than the predetermined number b is (S16 of Y), ECU 200, the motor 32 becomes the motor voltage V _p is approximately zero, thereby terminating the process in this flowchart is judged to have been stopped. if n is determined to be less than the predetermined number b is (S16 of N), ECU 200, in order to further reduce the motor voltage _{V p,} the process proceeds to S13 again.

ECU200, when stopping the motor 32, as shown from S13 to S16, and gradually decreases the rotational speed of the motor 32 by gradually reducing the motor voltage _{V p.}

(Second Embodiment)
FIG. 5 is a flowchart showing a process of the hydraulic control apparatus according to the second embodiment. The processing in this flowchart is repeated every predetermined time. Note that description of the same parts as in the first embodiment is omitted.

The ECU 200 determines whether or not the accumulator pressure P _acc is equal to or higher than a predetermined pressure P ₀ (S21). When it is determined that the accumulator pressure P _acc is less than the predetermined pressure P ₀ (N in S21), the ECU 200 determines that the motor 32 needs to be operated in order to increase the accumulator pressure P _acc. The process in the flowchart ends. When it is determined that the accumulator pressure P _acc is equal to or higher than the predetermined pressure P ₀ (Y in S21), the ECU 200 determines whether the motor voltage V _p is equal to or lower than the predetermined voltage V ₁ (S22). When it is determined that the motor voltage V _p is greater than the predetermined voltage V ₁ (N in S22), the ECU 200 determines that the motor 32 is not stopped and ends the processing in this flowchart.

When it is determined that the motor voltage V _p is equal to or lower than the predetermined voltage V ₁ (Y in S22), the ECU 200 determines that the accumulator pressure P _acc becomes sufficiently high and the motor 32 is stopped, and the plunger pump 400 Is disposed in a liquid path different from that in which the accumulator 49 and the reservoir tank 26 are communicated with each other, and a switching valve that opens or closes the communication between the accumulator 49 and the reservoir tank 26 is opened to allow communication between the accumulator 49 and the reservoir tank 26 (S23). ).

  As described above, when the motor 32 is operated, bubbles may be generated in the surrounding medium liquid such as the rotating shaft 422 of the hydraulic pressure generating mechanism. For this reason, in this embodiment, when the motor 32 is stopped and the operation of the plunger pump 400 is stopped, the accumulator 49 and the reservoir tank 26 are arranged in a liquid path different from the liquid path in which the plunger pump 400 is disposed. Communicate between them. Since the plunger pump 400 sucks the medium liquid from the reservoir tank 26, the accumulator pressure is transmitted to the liquid chamber 312 of the plunger pump 400 by communicating between the accumulator 49 and the reservoir tank 26, and is generated in the liquid chamber 312. Can cancel the negative pressure. In addition, it is possible to suppress the amount of bubbles in the liquid chamber 312 by causing minute bubbles generated in the medium liquid in the liquid chamber 312 to flow into the reservoir tank 26 and preventing the bubbles from staying in the liquid chamber 312. Thereby, the deterioration of the responsiveness of the pump by air bubbles can be suppressed.

  Here, the switching valve for communicating or blocking between the accumulator 49 and the reservoir tank 26 refers to the pressure-increasing linear valve 40 and the pressure-reducing linear valve 42. By opening the pressure-increasing linear valve 40 and the pressure-reducing linear valve 42, the accumulator 49 can be communicated with the reservoir tank 26 via the pressure-increasing linear valve 40 and the pressure-reducing linear valve 42. This can be transmitted to the liquid chamber 312 of the pump 400.

  On the front side, the right front wheel pressure increasing linear valve 40FR, the left front wheel pressure increasing linear valve 40FL, the right front wheel pressure reducing linear valve 42FR, and the left front wheel pressure reducing linear valve 42FL are normally closed linear valves. For this reason, ECU 200 opens these linear valves. At this time, considering that the brake may be operated by the driver, the right master cutoff valve 22FR and the left master cutoff valve 22FL are opened. As a result, when the brake is operated by the driver, the hydraulic pressure can be directly transmitted from the master cylinder 14 to the wheel cylinder 20.

  On the rear side, the left rear wheel pressure-increasing linear valve 40RL and the right rear wheel pressure-increasing linear valve 40RR are normally closed linear valves, but the left rear wheel pressure-reducing linear valve 42RL and the right rear wheel pressure-reducing linear valve 42RR. Is a normally open linear valve. For this reason, the ECU 200 opens only the left rear wheel pressure-increasing linear valve 40RL and the right rear wheel pressure-increasing linear valve 40RR.

(Third embodiment)
FIG. 6 is a flowchart showing the processing of the hydraulic pressure control apparatus according to the third embodiment. The processing in this flowchart is repeated every predetermined time. Note that a description of the same parts as those in the above-described embodiment is omitted.

The ECU 200 determines whether or not the accumulator pressure P _acc is equal to or higher than a predetermined pressure P ₀ (S31). When it is determined that the accumulator pressure P _acc is equal to or higher than the predetermined pressure P ₀ (Y in S31), the ECU 200 determines whether or not the motor voltage V _p is equal to or lower than the predetermined voltage V ₁ (S32). When it is determined that the accumulator pressure P _acc is less than the predetermined pressure P ₀ (N in S31), and when it is determined that the motor voltage V _p is greater than the predetermined voltage V ₁ (N in S32), this flowchart The process in is terminated.

When it is determined that the motor voltage V _p is equal to or lower than the predetermined voltage V ₁ (Y in S32), the ECU 200 determines that the accumulator pressure P _acc becomes sufficiently high and the motor 32 is stopped, and then the ECU 200 Determines whether or not the brake pedal 12 is off (S33). When it is determined that the brake pedal 12 is on (N in S33), the ECU 200 determines that there is a possibility that the motor 32 needs to be operated, and ends the processing in this flowchart.

If the brake pedal 12 is determined to be in the OFF state (S33 of Y), ECU 200, based on the detection result of the vehicle speed sensor (not shown), whether or not the speed V _c of the vehicle is the predetermined speed V ₂ or more Is determined (S34). If the velocity V _c of the vehicle is determined to be less than the predetermined speed V ₂ (S34 of N), determines that the background noise of the vehicle is low, and ends the processing in this flowchart. If the velocity V _c of the vehicle is determined that the predetermined speed V ₂ or more (S34 of Y), ECU 200 determines that the background noise of the vehicle becomes high, the liquid passage and the plunger pump 400 is disposed A switching valve that is arranged in a different liquid path and communicates or shuts off between the accumulator 49 and the reservoir tank 26 is opened, and the accumulator 49 and the reservoir tank 26 are communicated (S35). Note that the method of communicating between the accumulator 49 and the reservoir tank 26 is the same as S23 in FIG.

Accordingly, after the plunger pump 400 is activated and then stopped, the generated micro bubbles can be pushed to the reservoir tank 26 by transmitting the accumulator pressure P _acc to the liquid chamber 312 of the plunger pump 400.

The background noise refers to noise in the environment excluding the target noise. In the present embodiment, a predetermined linear valve is opened to allow communication between the accumulator 49 and the reservoir tank 26. This refers to the noise of the vehicle when the noise to be controlled is excluded. In general, the background noise increases as the speed of the vehicle increases. For this reason, a predetermined threshold value V ₂ is provided for the vehicle speed, and when the vehicle speed V _c becomes higher than the predetermined speed V ₂ , the predetermined linear valve is opened, whereby the linear valve The noise when opening the valve can be made inconspicuous.

(Fourth embodiment)
FIG. 7 is a flowchart showing a process of the hydraulic control apparatus according to the fourth embodiment. The processing in this flowchart is repeated every predetermined time. S41 to S43 are the same as S31 to S33 in FIG. In addition, the description of the same parts as those of the above-described embodiment will be omitted.

If the brake pedal 12 is determined to be in the OFF state (S43 of Y), ECU 200, based on the detection result of the engine speed sensor (not shown), the rotational speed of the vehicle engine R _E is a predetermined rotational speed R _It is determined whether the number is ₁ or more (S44). If the rotational speed R _E of the vehicle engine is determined to less than the predetermined rotational speed R ₁ (S44 in N), it determines that the background noise of the vehicle is low, and ends the processing in this flowchart. When it is determined that the vehicle engine speed R _E is greater than or equal to the predetermined speed R ₁ (Y in S44), the ECU 200 determines that the background noise of the vehicle is high, and the plunger pump 400 is disposed. A switching valve that is disposed in a liquid path different from the liquid path to communicate or block between the accumulator 49 and the reservoir tank 26 is opened, and the accumulator 49 and the reservoir tank 26 are communicated (S45). Note that the method of communicating between the accumulator 49 and the reservoir tank 26 is the same as S23 in FIG. Thereby, the generated fine bubbles can be swept away into the reservoir tank 26 as in the third embodiment.

Generally, the background noise increases as the rotational speed of the vehicle engine increases. Therefore, provided R ₁ is a predetermined threshold value to the speed of the vehicle, the rotational speed R _E of the vehicle engine when it is higher than the rotational speed R ₁ of the predetermined, opens a predetermined linear valve As a result, similar to the third embodiment, noise when the linear valve is opened can be made inconspicuous.

  The present invention is not limited to the above-described embodiments, and an appropriate combination of the elements of each embodiment is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to each embodiment based on the knowledge of those skilled in the art, and embodiments to which such modifications are added can also be included in the scope of the present invention. Here are some examples.

  The switching valve that is disposed in a liquid path different from the liquid path in which the plunger pump 400 is disposed and communicates or blocks between the accumulator 49 and the reservoir tank 26 is not the pressure-increasing linear valve 40 and the pressure-decreasing linear valve 42, A switching valve provided in a separate liquid path may be used. Thereby, the generation of bubbles in the plunger pump 400 can be reduced while the control of the hydraulic pressure to the wheel cylinder 20 by the pressure-increasing linear valve 40 and the pressure-decreasing linear valve 42 is made effective.

  In the third and fourth embodiments, noise detection means such as a noise meter provided in the vehicle may be used to determine that the background noise of the vehicle has increased. Thereby, background noise can be detected more accurately, and driving can be made more comfortable.

1 is an overall configuration diagram of a hydraulic system according to a first embodiment. It is a functional block diagram of ECU which concerns on 1st Embodiment. 1 is an overall configuration diagram of a plunger pump according to a first embodiment. It is a flowchart which shows the process of stop control of the hydraulic control apparatus which concerns on 1st Embodiment. It is a flowchart which shows the process of the hydraulic control apparatus which concerns on 2nd Embodiment. It is a flowchart which shows the process of the hydraulic control apparatus which concerns on 3rd Embodiment. It is a flowchart which shows the process of the hydraulic control apparatus which concerns on 4th Embodiment.

Explanation of symbols

  12 brake pedal, 14 master cylinder, 20 wheel cylinder, 22 master shut-off valve, 26 reservoir tank, 32 motor, 40 linear valve for pressure increase, 42 linear valve for pressure reduction, 49 accumulator, 51 accumulator pressure sensor, 200 electronic control unit, 312 Liquid chamber, 400 plunger pump.

Claims (9)

A hydraulic control device applied to a vehicle brake device,
A pump including a fluid pressure generating mechanism disposed in the medium liquid;
A motor for driving the fluid pressure generating mechanism to generate fluid pressure;
Motor control means for controlling the rotation of the motor,
The hydraulic pressure generating mechanism includes an eccentric cam, a piston that contacts the eccentric cam, a rotating shaft that transmits the drive of the motor to the eccentric cam, and a bearing that slides on the rotating shaft, When the eccentric cam is driven, the piston reciprocates to generate a hydraulic pressure,
When stopping the pump, the motor control means gradually decreases the duty of supplying current to the motor, thereby gradually decreasing the rotation speed of the motor to stop the rotation of the motor. A hydraulic control device. A switching valve that is disposed in a different fluid path from the fluid path in which the fluid pressure generating mechanism is disposed, and that communicates or shuts off between the accumulator and the reservoir;
The pump is in communication with the reservoir, and is provided to apply hydraulic pressure to the accumulator by driving the hydraulic pressure generating mechanism,
The hydraulic control device according to claim 1, wherein the switching valve communicates between the accumulator and the reservoir when the pump is stopped. The switching valve includes a pressure increasing valve for communicating or blocking between the accumulator and the wheel cylinder, and a pressure reducing valve for communicating or blocking between the wheel cylinder and the reservoir, and the pressure increasing valve and the The hydraulic pressure control apparatus according to claim 2 , wherein the accumulator and the reservoir are communicated by opening a pressure reducing valve. The hydraulic pressure generating mechanism includes an eccentric cam, a piston that contacts the eccentric cam, a rotating shaft that transmits driving to the eccentric cam, and a bearing that slides on the rotating shaft, and the eccentric cam is driven. by being, fluid pressure control device as claimed in claim 2 or 3, characterized in that said piston to generate hydraulic performs reciprocating motion. A switching valve that is disposed in a different fluid path from the fluid path in which the fluid pressure generating mechanism is disposed, and that communicates or shuts off between the accumulator and the reservoir;
The pump is in communication with the reservoir, and is provided to apply hydraulic pressure to the accumulator by driving the hydraulic pressure generating mechanism,
2. The hydraulic pressure according to claim 1, wherein the switching valve communicates between the accumulator and the reservoir when the pump is stopped and a background noise of the vehicle is high. Control device. 6. The hydraulic control apparatus according to claim 5 , wherein the predetermined state is when the speed of the vehicle becomes greater than a predetermined value. 6. The hydraulic control apparatus according to claim 5 , wherein the predetermined state is when the rotational speed of the engine of the vehicle becomes larger than a predetermined value. The switching valve includes a pressure increasing valve for communicating or blocking between the accumulator and the wheel cylinder, and a pressure reducing valve for communicating or blocking between the wheel cylinder and the reservoir, and the pressure increasing valve and the by opening the pressure reducing valve, the hydraulic control device according to any one of claims 5 to 7, characterized in that communicating between said accumulator and said reservoir. The hydraulic pressure generating mechanism includes an eccentric cam, a piston that contacts the eccentric cam, a rotating shaft that transmits driving to the eccentric cam, and a bearing that slides on the rotating shaft, and the eccentric cam is driven. by being, fluid pressure control device as claimed in any one of claims 5 to 8, characterized in that said piston to generate hydraulic performs reciprocating motion.

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